Impact hammer

ABSTRACT

An impact hammer includes a ram mounted in a cylindrical housing for impact engagement with an anvil and tool supported by the housing. The ram is driven by compressed gas confined within a chamber defined at the inner end of the hammer housing. The ram is cocked to compress the gas by means of a cylindrical cam mounted on the ram and drivingly engaged by cam rollers rotatably mounted in the housing. The gas chamber is formed between the inserted end of the hammer ram and the closed end of the hammer jacket by a hat-shaped flexible diaphragm, the rim of which is secured to the jacket and the crown top of which is secured to the inserted end of the impact ram.

United States Patent [72] inventor Russell John Dorm 2,396,185 3/1946 Mannerstedt et al. 173/119 Aurora, Colo. 3,162,252 12/1964 Cobi 173/120 [21] Appl. No. 11,110 3,186,498 6/1965 Roll 173/123 [22] Filed Feb. 13,1970 3,302,732 2/1967 Roll 173/123 [45] Patented June 1 1 3,321,033 4/1967 Benuska et a1 173/119 [73] Asslgnee CBS Corporation Primary Examiner-James A. Leppink Attorney-Drake and Crandeli [54] IMPACT HAMMER 2 Claims, 5 Drawing Figs.

[52] US. Cl 173/119, ABSTRACT: An impact hammer includes a ram mounted i 3 173/123 cylindrical housin for im act en a ement with an anvil and 825d 9 g p g g [51] Int. Cl tool Supported by the housing The ram is driven by 825d 11/00 pressed gas confined within a chamber defined at the inner [50] Fleld of Search 173/116, end f the hammer housing h ram is cocked to compress l 123 the gas by means ofa cylindrical cam mounted on the ram and drivingly engaged by cam rollers rotatably mounted in the [56] References cued housing. The gas chamber is formed between the inserted end UNITED STATES PATENTS of the hammer ram and the closed end of the hammer jacket 1,497,635 6/1924 Parrish 173/119 by a hat-shaped flexible diaphragm, the rim of which is 1,553,593 /1 25 Cooley 173/119 secured to the jacket and the crown top of which is secured to 2,317,158 4/1943 Westover 173/119 the inserted end ofthe impact ram.

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sum 1 nr 2 ATTORNEYS PATENTEDJUH 819?! 3583498 SHEET 2 BF 2 RUSSELL-- JOHN DORN BY 49% @%M ATTORNEYS IMPACT HAMMER BACKGROUND OF THE INVENTION The present invention relates to compressible fluid powered rotary cam actuated impact hammers, and more particularly to an improved gas chamber construction for such hammers.

Impact hammers involving an impact ram mounted within a jacket and driven by a compressed medium such as a compressible gas, compression spring, or like power element, are well known in the art. Illustrative mechanisms are shown in the prior art. See, for example, U.S. Pat No. 3,321,033, issued May 23, I967, to G. .l. Benuska et al., for Motor Powered Air Hammer;" U.S. Pat. No. 1,497,635, issued June 10, I924, to F. H. Parrish, for Air Hammer; U.S. Pat. No. l,553,598, issued Sept. l5, I925, to F. D. Cooley, for Pneumatic Hammer; U.S. Pat. No. 3,l86,498, issued June 1, 1965, to .l. A. Roll, for Impact Tool;" and U.S. Pat. No. 3,302,732, issued Feb. 7, I967, to J. A. Roll, for Impact Tool." In many of these patents, the hammer or ram is cocked to compress the driving medium, such as compressed air, by means of motor driven cams. The cams are provided with a dropoff to allow the compressed medium to drive the hammer against a tool anvil. A serious problem encountered by the prior art constructions utilizing a compressed gas involves leakage and the resultant loss of gas past the seal construction between the inserted end of the impact ram and the hammer jacket.

OBJECTS OF THE INVENTION The principal object of the present invention is to provide an improved compressible fluid seal construction for an impact hammer of the type involving an impact ram inserted into the closed end housing. More particularly, it is an object of the present invention to provide an improved seal construction of the foregoing character which is substantially leakproof, is rugged, requires a minimum of maintenance and provides a positive sealing action between hammer jacket and an inserted end of impact ram.

Another and more specific object of the present invention is to prevent the loss of compressible fluid and resultant diminution of hammer power in compressible fluid powered impact hammers.

Other objects and advantages of the present invention will become apparent from the following description.

SUMMARY OF THE INVENTION The foregoing objects are accomplished by provision, in a compressible fluid-powered impact hammer embodying a generally cylindrical jacket having an enclosed end with an impact ram reciprocally mounted therein, of a hat-shaped flexible diaphragm having a rim and a crown, with the rim securely sealed to the jacket and the top of the crown securely sealed to the inserted end of the impact ram. The closed chamber thus defined is filled with a compressible fluid. The impact ram is driven inwardly by a cam mechanism to compress the fluid. The cam includes a dropoff section which allows the hammer to move outwardly under the driving force of the compressed fluid. At the outer end of the jacket there is mounted an anvil which carries an appropriate tool. The hammer strikes the anvil and the energy is transmitted therethrough to the tool for the intended purpose.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal detailed section view of an impact hammer embodying the present invention.

FIG. 2 is a section view, similar to that shown in Fig. l, but in generally schematic form and illustrating the hammer in a retracted position.

FIG. 3 is a section view similar to Figure 2 but taken looking in the opposite direction, to illustrate the cam configuration, and showing the ram in a partially extended position.

DESCRIPTION OF THE PREFERRED EMBODIMENT There is shown in the drawings, with particular reference to FIG. I, a compressible fluid actuated impact hammer. Hammers of this type are particularly adapted for mounting on a backhoe in place of the the backhoe bucket/The hammer may, however, be mounted upon an extensible boom carried by any dirigible automotive vehicle. a

The impact hammer embodied in the present illustration'is demonstrated in detail in the drawings, and comprises an outer cylindrical jacket 10 defining an internal boreor cylindrical chamber 11 in which is telescopingly and slidingly received an impact ram 12. The inner end of the cylinder housing 10 is closed by an end closure cap 14. The cap 14 includes an axially extending fluid chamber sleeve 15, formed as an integral part thereof, and supporting a sleeve bearing 16 which slidingly supports the inner end of the ram 12. At its outer end, the cylindrical housing 10 mounts an anvil and tool supporting structure 18 in which is mounted an anvil 19, adapted to be engaged by the impact end 20 of the ram 12. A tool 21 of any desired character is carried by the external end of the anvil 19. The impact end 20 of the ram 12 is supported in the cylindrical housing 10 for reciprocal sliding movement therein, by means of a bearing assembly 22, the purpose of which will be described below. This bearing assembly includes a ram supporting sleeve bearing 24, slidingly engaging and supporting external surface of the ram 12 for reciprocal sliding movement within the cylinder 10.

For powering the ram into impact engagement with the anvil l9, and thereby impart a working impact force to the tool 21, a compressed fluid driving mechanism is utilized. A fluid chamber housing 26 is mounted on the open end of the closure sleeve 15 and defines with the sleeve 15 and ram 12 a chamber 25 for receiving a compressible fluid, such as nitrogen gas or air. The gas chamber housing 26 is a generally cup-shaped member, having an outwardly extending annular flange 28 defined at its peripheral edge for use in mounting the housing 26 on the end of the sleeve 15. The external surface of the sleeve 15 is threaded for engagement with a sleeve nut 29, which slips over the chamber flange 28 and clamps the same tightly against the sleeve 15. A filling valve 30 of conventional construction is provided on the gas chamber housing 26 for supplying a compressible fluid such as compressed gas to the chamber 25.

The ram is actuated to compress the gas into chamber 25 by means of any appropriate mechanism, a motor driven cam mechanism being one illustrative power source. To this end, a sleeve-shaped cam body 32 is secured to the ram at a point intermediate its ends by appropriate pins or bolts 34. The cam sleeve defines circumferentially spaced guide slots 35 for guiding engagement with guide rollers 36 secured on a guide roller mounting sleeve 38 integral with the end closure 14, and extending inwardly within the cylinder housing 10. These guide rollers prevent the ram from turning during operation of the cam.

The cam body 32 in turn defines a cam surface 40 which is engaged by cam rollers 41 carried on a roller body 42 and supported for rotary movement within the cylinder housing 10 by the bearing assembly 22. The bearing assembly 22 includes an inner bearing sleeve 44, an outer bearing sleeve 45 and interposed radial and thrust bearings 46. The cam roller body 42 is rotated to roll the cam roller 41 against the cam surface 40, by a motor 48 mounted externally on the cylindrical housing 10 and operatively connected to the cam roller body 42 by a chain and sprocket mechanism. This mechanism includes a driving gear 49 on the motor shaft a cam sprocket 15 on the cam roller body 42 and a drive chain 51 interconnecting the drive gear 49 and sprocket 50.

Rotation of the cam roller body 42 causes the cam M to ride on the cam surface 40 and force the ram 12 inwardly to compress gas contained in the gas chamber 25. At one point in its circumferential movement, the cam surface 40 defines an abrupt dropoff which allows the compressed gas within the chamber 25 to power the ram forwardly into working impact with the anvil 19. The cam roller body continues to rotate, and the operation of compressing the gas and allowing the compressed gas to expand to drive the ram into impact engagement with the anvil is cyclically repeated.

In order to provide an effective seal between the cylinder housing and the ram 12 to seal the compressible fluid or gas within the chamber 25, the present invention utilizes a hatshaped diaphragm of the type shown in FIG. 5. This diaphragm 54 comprises a crown 55, having generally cylindrical sidewalls 56 and crown top 58. At the bottom edge of the cylindrical crown sidewall 56, the diaphragm defines an outwardly extending annular rim or flange 59. In mounting the hat diaphragm 54 in place, the rim 59 is clamped tightly between the flange 28 on the gas chamber housing 26 and the outer end of the sleeve 15, by clamping the sleeve nut 29 tightly in place. The hat diaphragm is, in turn, sealed to the inner end of the ram. For this purpose, an aperture 60 is provided in the crown top 58 which engages over a threaded bolt 61 on the end of the ram 12. The crown top 58 is thus generally annular in shape. A sealing washer 62 and castle nut 64 tightly clamp the crown top 58 to the end of the ram 12.

With the hat diaphragm clamped securely in place, it will be observed that the gas chamber 75 is completely enclosed and sealed against leakage. During compression of the gas in the chamber 25, the sidewall 56 of the diaphragm crown 55 is folded back on itself and provides an effective and efficient moving seal. The thickness of the bearing 16, and the spacing between the external surface of ram 12 and the internal surface of the sleeve is such that a double thickness of the diaphragm wall is accommodated. The diaphragm is sufficiently resilient so that it rides along the surface of the ram and closure sleeve, the folded edge, indicated at 65, traveling along the facing surfaces of the ram 12 and sleeve is to provide a folding or traveling seal between the moving ram 12 and the stationery sleeve 15.

The hammer may desirably include shock absorbing means such as the shock absorbing spring 66 and further may make provisions for release and exchange of the tool such as the tool receiving socket 68 and pin 69.

While a certain illustrative embodiment of the present invention has been shown in the drawings and described above in considerable detail, it should be understood that there is no intention to limit the invention to a specific form disclosed. On the contrary, the intention is to cover all modifications, alternative constructions, equivalents and uses falling within the spirit and scope of the invention as expressed in the appended claims.

lclaim:

1. In a compressible fluid powered impact hammer comprising a generally cylindrical jacket having a closed end, an impact ram reciprocally mounted in said jacket, tool engaging anvil means on the open end of said jacket for impact engagement by the outer end of said ram, the inner end of said ram defining a compressible fluid containing chamber with the closed end of said jacket, and means for cyclically driving said ram into said jacket to compress the fluid in said chamber and for releasing said ram for outward impact movement under the driving influence of compressed fluid, the combination therewith of a hat-shaped flexible diaphragm having a rim and a crown, means sealing the rim of said diaphragm to said jacket at a point spaced from the closed end thereof, and means sealing the crown top of said diaphragm to the inner inserted end of said ram, whereby said diaphragm provides an expandible and contractable seal between the ram and the jacket.

2. A compressible fluid powered impact hammer as defined in claim 1 wherein said hat-shaped flexible diaphragm includes a generally annular crown top portion for sealing engagement with the ram.

g;;g- UNITED STATES PATEWT ,O FICE CERTIFICATE OF CORRECTION Patent No. 3,583,498 Dated June 8, 1971 Inventor(s) Russell John Dorn It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Change the name of the inventor from "Russell John Dorm" to read -Russe1l John D0rn-.

Signed and sealed this 28th day of September 1971.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Acting Commissioner of Patents 

1. In a compressible fluid powered impact hammer comprising a generally cylindrical jacket having a closed end, an impact ram reciprocally mounted in said jacket, tool engaging anvil means on the open end of said jacket for impact engagement by the outer end of said ram, the inner end of said ram defining a compressible fluid containing chamber with the closed end of said jacket, and means for cyclically driving said ram into said jacket to compress the fluid in said chamber and for releasing said ram for outward impact movement under the driving influence of compressed fluid, the combination therewith of a hat-shaped flexible diaphragm having a rim and a crown, means sealing the rim of said diaphragm to said jacket at a point spaced from the closed end thereof, and means sealing the crown top of said diaphragm to the inner inserted end of said ram, whereby said diaphragm provides an expandible and contractable seal between the ram and the jacket.
 2. A compressible fluid powered impact hammer as defined in claim 1 wherein said hat-shaped flexible diaphragm includes a generally annular crown top portion for sealing engagement with the ram. 